The proposed project aims to provide a peptide ELISA as a single step serodiagnostic assay for Lyme disease, to replace the current two-tier testing protocol recommended by CDC in 1994. This single step test will eliminate the deficiencies in cost efficiency, reproducibility and objectivity, throughput and accuracy associated with the use of the Lyme Western Blot as the second step in the two-tier protocol. An ELISA based on peptides including the C6 peptide of the antigenic Borrelia protein VlsE and a peptide derived from the OspC protein will be developed. The sensitivity of the peptide ELISA in detection of early Lyme disease will be determined precisely as a function of time after infection through an analysis of longitudinal serum samples from infected rhesus monkeys, which provide a model for human disease. The peptide ELISA will be compared directly with the two-tier method in a clinical evaluation of well-characterized human sera from patients with Lyme disease in different stages, confirmed by culture, and in a prospective study of new patients followed over time. This will be the first study of its kind aimed at simplifying and improving the diagnostic approach to Lyme disease using an accurate and cost-efficient peptide ELISA. PROPOSED COMMERCIAL APPLICATION: NOT AVAILABLE